Inkjet printers typically utilize one or more printheads each including an array of orifices (or nozzles) through which ink is ejected onto paper or other printing media to form an image. The printheads may be supported by a moveable carriage that traverses back and forth across the width of the paper as the paper is fed through the printer during printing operations, or the printheads may remain stationary during printing operations, as in a page-wide array of printheads. The printheads may be an integral part of a print cartridge or may be a discrete assembly to which ink is supplied from a separate, and often replaceable, ink container. For printers that utilize replaceable ink containers, proper positioning of the replaceable ink containers in the printer may be provided by a keying arrangement.